TO 1F-4E-1

NOSE GEAR STEERING

An electrically controlled, hydraulically operated nose
gear steering system is installed in the aircraft. The
steering actuator is a vane type hydraulic motor on the
nose gear strut. It is geared through a planetary gear train
to the strut and performs both steering and damping. A
bypass valve in the steer-damper manifold directs
hydraulic fluid to an electrically controlled hydraulic
servo valve, This valve directs fluid to the actuator which
can be pressured on either side as directed. For the
damping mode, the bypass valve traps the fluid in the
actuator and channels it through damping orifices which
absorb energy. When the control stick grip nose gear
steering button is held down, with the main gear strut
compressed, and the gear handle is in the down position,
the system is energized and steering is commanded by
rudder pedal movement. The limit of the nose gear
steering system is 70° on each side of center; however, with
the steering unit deenergized, the nose gear may be
rotated 360° for towing or positioning the aircraft. When
energized with the nose gear in any position, the nose gear
will quickly return to the position commanded by the
rudder pedals. The system contains a failure detection
circuit which, upon detection of an electrical short or open,
or intermittent outputs from system electrical
components, will shut off hydraulic pressure to the system.
In this event, the nose wheel reverts to a free swivel
condition. When the lower UHF antenna is selected, the
nose gear steering may be erratic or inoperative;
therefore, the upper UHF antenna should be selected
before engaging the nose gear steering.

CAUTION

If no response is noted or unscheduled steering
commands occur with nose gear steering engaged,
release the nose gear steering button and do not
reengage. The aircraft should not be taxied or
flown with inoperative nose gear steering, except
in an emergency.

WHEEL BRAKE SYSTEM

The main landing gear wheels are equipped with full
powered brakes operated by toe action on the rudder
pedals which meters utility hydraulic pressure to the
brakes. The brake control valves are in the nose gear well
and operate through a linkage arrangement to the rudder
pedals. The brake control valves are capable of directing
full utility system pressure to the wheel brakes with full
pedal deflection. The amount of brake pedal force and the
amount of utility pressure directed to the wheel brakes are
proportional to pedal displacement. An anti-skid system is
incorporated in the normal brake system to prevent wheel
skid. An emergency brake system, when actuated,
discharges accurnulator hydraulic pressure to the brakes
in the event of utility system failure. Operation of the
brakes on the emergency system is identical to the normal
system for the duration of the hydraulic accumulator
supply. Anti-skid protection is not available on the
emergency brale system. Each main landing wheel
contains chree fuse plugs to protect against tire explosion.
If the brutes are used excessively, causing overheating of

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the wheels and tires, the fuse plugs should melt and let the
tire go flat before a tire explosion can occur.

ANTI-SKID SYSTEM

The aircraft is equipped with an electrically controlled
anti-gkid system which prevents wheel skid. The system
detects the start of a skid condition at the wheels and
automatically releases the brake pressure in proportion to
the severity of the skid. Use of the anti-skid system offers
protection from skids, and can provide consistently
shorter landing rolls for all runway conditions. The system
provides positive assurance that the wheels have an
opportunity to spin up at touchdown, even if inadvertent
brake pressure is applied and elimination of a single wheel
experiencing a gradual or stair step speed reduction due to
extremely slippery conditions. The system has a fail-safe
circuit that automatically reverts the system to manual
braking in the event any of the electrical components of
the system fail. The system is activated by placing the
anti-skid control switch ON and lowering the landing
gear. It may be disengaged by placing the anti-skid control
switch to OFF, or by holding either emergency quick
release lever depressed. An ANTI-SKID INOPERATIVE
light illuminates when the system is not activated.

NOTE

@ The system does not provide full skid protection
below 30 knots.

® During maximum braking on a dry runway with
speed below 50 knots, a severe “BANG BANG”
may be heard. This is normal for low speed
operation during maximum braking and should
not be interpreted as an anti-skid malfunction.

@® Pulling the ARI circuit breaker, on the front
cockpit left subpanel, will disconnect control
power to the anti-skid system.

Anti-Skid Control Switch

This two-position toggle switch is on the left console, front
cockpit, adjacent to the oxygen quantity gage. When the
switch is ON and the landing gear handle is down, power
is supplied to the system. The anti-skid system may be
shut off by placing the anti-skid control switch to OFF.

Anti-Skid Inoperative Light

An ANTI-SKID INOPERATIVE light is on the left
console in the front cockpit. The light illuminates any time
the landing gear handle is down and the anti-skid switch
is OFF, circuit continuity is not complete, or when the
emergency quick release lever is held depressed. Anytime
the light illuminates steady, the anti-skid system is
inoperative and the control switch should be placed to
OFF. If the light does not illuminate, it can only be
assumed that the anti-skid circuitry is good. Anti-skid
protection still may not be available due to system
component failure. The master caution light does not
illuminate in conjunction with the ANTI-SKID
INOPERATIVE light.